Syntax highlighting, as well as other code insight features like find usages, refactorings, code generation, and code analysis may depend on the set of preprocessor definitions which determine the rules of parsing and resolving your code. These rules are also known as resolve context.
In the case of CMake projects, the resolve context is defined by the corresponding CMake profile.
Switch resolve context for the currently opened file (CMake projects)
Select the desired configuration of profile from the Run/Debug Configuration switcher.
Use the context switcher in the right-bottom corner of the status bar:
Select <Auto> to restore the automatic selection after manual changes.